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Discussion Starter · #1 ·
Gads...

OK, I am rebuilding the infamous '75 Ascona SportWagon engine. Or at least trying to, but it's starting to look bad. Aside from the problems I have chronicled to date (spun rod bearing, doubled-up bearing shell, bent rods and caps, bent crank pulley, worn cam & lifters, buggered rocker stud, missing clutch pressure plate), I have a few new problems.

I dropped the disassembled engine parts off at a local (and highly recommended) machine shop. The guy even knew the Opel CIH engine. All I needed, I thought, were the parts tank-cleaned, the new rods pressed on, the crank ground to fit the under-size bearings I scored off eBay, and the cylinders honed. I was a bit worried that the cylinders might be a bit too worn, but hey, this is an ECONOMICAL rebuild, for a car that is, at best, a daily driver, but will likely never be a show nor race car.

But he knew the CIH well enough that he magnufluxed the head before he went too far, and, lo and behold, the damn thing is cracked. Sorry for the language. Just like I have read here countless times, the later head is prone to cracking along the exhaust seat, and this one is cracked through to the coolant passage. So it is JUNK. Well, Kat had warned me that it had been overheated at least once. Lesson learned.

He has a spare Opel CIH head (who'd have THUNK!!), albeit an earlier 10 bolt version. He doesn't know which year it is, and I haven't seen it yet. So, here is my question. If it is the '71/'72 head, with the extra bolt holes in the casting but not drilled, can I use it with the '75 timing chain case? Can I even use the earliest head? Or do I have to change out the timing chain case to the earlier (10 bolt head) version to use the earlier head? Any special instructions to follow if I can use it? It would seem that the earlier head and later chain case have the same outline, so why aren't they interchangeable? I have read that the later head gasket is usable with the earlier head and chain case, so can I use a later head gasket and chain case with the earlier head? Or is this just wishful thinking?

Apart from the cracked head, I apparently also have (at least) one excessively worn piston, and possibly several worn wrist pins. And I might also have cylinders that are also too far gone. Clearly, this is NOT looking like an ECONOMICAL engine rebuild! If I do need to over-size the pistons and pins, can you please remind me what my choices are for substitute pistons, rather than expensive OGTS Opel pistons? I am a die hard OGTS supporter, but $380 USD (over $500 CAD!) for a set of pistons/pins/rings seems like a cry for a divorce lawyer. I recall hearing about the Chevy 305 (and 265?) pistons, but I believe they require at least an off-set crank grind (which does have the benefit of increase stroke, but increased cost). Are there any other CHEAP pistons that will work? I have heard about an early Buick piston that also might work (John Warga's 2.3 conversion) but it DEFINITELY requires an off-set grind.

Thanks for the help. Until the next thing I find wrong with this darn car (see, I have calmed down a bit and have quit swearing like a rig-pig)
 

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crazy opeler
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On the motor that I rebuilt I had an early head (69) and a later model block and timing chain(73), I was upgrading the motor to 2.0l and OGTS sent me a 2.0l head gasket and a 1.5L head gasket, I had to use the 2.0l gasket in the piston area. Where the timing chain meets the head I used the 1.5L gasket, it was a bit thicker and made up for the difference in the early and later heads. Strange that I needed the earlier 1.5 gasket to make the later model block work.
 

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The answers to your questions are as follows:

By all means use the early head, check out the cam and lifter situation on it, unless you have another set for it. You should also look into the hardened seats for the early head.

Yes your newer timing cover can be used with a newer head gasket. One small note is to use a dab of RTV in the empty bolt holes.

As for your pistons call OGTS and ask Gil about pistons. I was prepared for the full price on my current 9 to 1's and he recommended a very slightly used set at a very good price. For wrist pins I would go new there. Who knows ask about 20 over while you have him on the phone, come to think of it that is exactly what he sold me. Seems like the set was under 100 bucks.
 

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i am not quite sure how much cheaper using the chevy 265 pistons are but here it is:
about 40 bucks a piston: 160 bucks
rings were 40 bucks for a set of 8
so thats 220 and you have to have the rods opened up to accept chevy wrist pins, and the crank does not have to be offset ground. you'll probably have to shave the pistons a little bit though, the 265 pistons only come in flat tops with the 4 valve relief. so you run about 220, plus opening up rods and shaving about .020 off the pistons top, so say 300 or so to completely do chevy pistons, boring for me was 16 bucks a hole.
 

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Ah, the motor game

I've actually spent the last few weeks researching this very topic, so here's the distilation of what I found:

265 Chevy pistons are pretty darn close, they just stick out the block 0.020" and have too big a wrist pin. They can be ordered from Venolia with Ford wrist pin diameters, though, and a recesed head too that makes it so you only have to cut down the crown. Might save you a little overall.

A 0.060" over Ford 272 ('55-57) piston already has the smaller pin and is stock at 0.011" below deck heith with flat head. Should work, but the pistons, though not terribly expensive (@$55 each), are a custom order and I haven't had the cash sitting around to order one to experiment with.

Chevy 305 pistons, and the 6-cylinder equivalent the Chevy (not buick) 3.8 v-6, are a good fit on bore, but they also have the larger Chevy wrist pins and they are 0.210" below the deck, for about a 4:1 compression ratio with stock rods. These pistons can also be ordered in a shorter height, if desired, for @3.3:1 CR and @.5" below deck height

This is where the requirement for new rods comes in, and the low cost of the pistons begins to get muddied. Opel rods are rather small bore for the v-8 crowd and rather large for the 4-banger crowd. The real kicker, though is the rod width. Opel rods are 0.9789" wide, which wierd compared to most other rods.

Neon rods might work, and are about the closest to Opel width at 1.032", but their pin diameter is only 0.826" compared to the Chevy 0.927" and the Opel 0.906". They're also a hair on the long side, but the motor can be de-stroked some due to the smaller big end (1.889" vs. the Opel 2.0464") to make it work, or stroked the same way to make the shorter pistons work. Still have the pin diameter issue, and the cost of custom ordering a bunch of parts before you install with no real idea if the machinist is going to be able to make it work.

You could also order a set of stroker Ford rods, for the common 347 stroker (5.400" or 5.315"), with Chevy pin diameters and specified for Chevy journals. This would have a 2.00" crank diameter, and the right size piston pins, but stock Ford width is 0.8315" and I'm not sure whether you'ld get that width or the Chevy 0.940" width. This would put the 305 piston over 0.090" out of the block, but the crown on most is about that thickness, so you could machine it down to a flat top and be OK. These rods come in sets of 8, and can be had in the $350 range on e-vil-bay new, so 2 buyers splitting the cost could probably make it cost effective.

A stroker VW rod is also available with the the 2.00" chevy journal and a 5.3" or 5.4" length, but is also fairly narrow on the bottom end width. Unfortunatly VW's use a 0.8something" pin that is way too small for 305 pistons.

Then you're to the Acura rod option that was recommended by Bob L. in an older post. They are 5.430 length, which is good, and 1.771" crank, which gives your machinist a lot of room to stroke the motor but cuts the journal down by over 1/4." They also come with 0.826" pins and 0.858" crank width, which is significantly narrower than the Opel, but if the machinist only cuts the journal down this wide, and leaves it as is for the rest, it should be fine. Not too sure what you'ld do iwth the pins, though, so it might only work with special ordered pistons.

The results:
-For ease, get the 265 Chevy pistons, either ordered with Ford pins straight from venolia or stock, have the crown cut and the rod machined bigger, bore the motor some and drive away. Probably will save you $20-50 over new pistons from OGTS in the end.
-If you're not in a hurry, order one Ford piston and have the machinist check it out. If it works great, let us all know, order 3 more, and put the motor together and drive home. Might save you $150-200 over OGTS, but might just cost you $50 to try. (I have a few other suppliers I can get you info for if your local shop can't get these.)
-If you want more displacement at the same time, try the 305 piston trick with some sort of other rod. You'll proably want to get a brave friend to split the cost of the experiment with you, and if you go this way, give me a call and we'll work out a sweet deal on a set of 8 brand new cast 305 pistons getting dusty in the back room.

Man, this got long winded quick.
 

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Old Opeler
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ACL "Opel" 1900 Pistons

I've been looking around here in New Zealand and have found a small supply of 93mm bore oversized pistons (+010; +020 and +040") for the Holden Torana 19S "Opel" motor that was used from 1972-79 as their base motor. They are 9:1 CR flat-tops and come complete with cast rings and pins.

The best thing is the price - around $US200 plus postage unfortunately as New Zealand is a long way from you guys.
I'll check what postage would be on Monday if anyone is interested.

I have one set for myself,to use in a standard keep it going engine and they are a quality standard type cast piston made in Australia. Someone here must have stockpiled a few sets then found that everyone tossed out the 19S motor and replaced it with a Holden six cylinder or V8. The 19S was known as a bit of a "slug" in the Torana as the car is about the size of a Chevy Nova! However it has given me a source of 19S engines and even a couple of TH180 auto transmissions for my auto GT.

I am an auto man due to a "blown" knee caused by 3,800 lb Chev clutches and mechanical clutch links in earlier street racing days.

I am looking at Neon rods with 1.260" pin height 305 pistons and 77.7 stroke offset grind 1.9 crank for 2.2 litres for my 'best' motor.
Some good info in earlier posts!
 

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Discussion Starter · #8 ·
This post was made on the classicopels site:

Edwin,

I have heard about head repairs, but have never attempted it. What method are you advocating (aside from welding)? Some sort of "threading"? Sorry, but I am not getting it.

As for using older 10-bolt heads with later 12-bolt head chain
cases, it seems (according to the responses I have been getting) that the big difference is the clearance between the chain case and the head. I believe the early version has more clearance, and the corresponding head gasket uses a cork layer to fill and seal the gap (at least that is what my '71 FelPro Head gasket has). The later version 12-bolt head gasket I have (from a 1.6 litre, in case anyone wants one, useless to me) doesn't have the cork layer. So I suspect (confirmed by the OpelMeister, Bob Legere) that the only difference is the height of the chain case, and the heads are virtually interchangeable. Now I presume that the 12-bolt case sits higher than the 10-bolt version. But Chris Blust indicated the opposite. So that doesn't go around. Can anyone confirm which chain case has less clearance?
 

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Old Opeler
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Head Repairs

There was a system known as "Metalock" that used a shaped insert that fitted into a line of carefully drilled holes and was peened into place in an attempt to fill up and seal cracks in cast iron. Old sidevalve V8 and Studebaker sixes were often riddled
with it - sometimes with valve seat inserts fitted over top of it all.

As horrible as it sounds - usually just enough to get the car sold so that the next guy could replace the stuffed block!

It can work on waterjackets but the greater expansion in the valve seat area simply defeats it.

Learnt a long time ago that a cracked seat means the part is junk and replacement is really the only option.

It seems that the front of the Opel 19S engine family had a leak problem from day one and Opels attempt to fix it by putting a couple of capscrews there was accompanied by a different front cover and at the same time GM's infamous "chilled" valve seats.

The heads were cast upside down with cast iron "chills" in the mould under the seat area so that the metal around the seats was cooled more quickly ( ie: "chilled" ) which lead to high stresses in that area and cracks! Ask anyone who has had experience with early 305 Chev heads. All an attempt to "harden" the seats for unleaded gas without actually going to the expense of fitting inserts. I blame the "greenies" and lead-free gas.

Welding the heads can work but only if the guy doing it is a magician and uses the correct proceedure. The head must be brought up to almost red-hot and a eutectic rod used but all this heat means warping and more stresses so that more cracks are a sure thing. Get another head - several of them till you get one that is not cracked! Such is life, love and GM's finest.........:D
 

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crazy opeler
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Hmmm maybe I was wrong, now that I hink about it, I think it was a 71' block and timing cover chain. If that makes any difference.
 

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bolts

I would be willing to bet there is no real difference at all in clearance, Keith, at not one you could measure with parts in hand.

On the older motors, there is nothing really connecting the head to the timing cover. I would suspect that instead of properly compressing the head gasket, the timing cover moves ever so slightly with respect to the head, opening the gap and requiring the extra cork portion attached to the gasket to seal properly.

In the case of the newer motor, the head actually is bolted to the timing cover, and that gap between them is compressed by a couple of decent-sized bolts. This would ensure the two parts are pulled together and sealed well, and there is no flxing or movement of either the end of the head or the timing cover.

In your situation, I would recommend either using the older head gasket with the cork, or the newer one and either adding a thin cork shim or the fromt portion of the older gasket.
 

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The early 10 bolt head timing cover use a head gasket with a THICKER extra piece of cork attached where the timing cover,block & head meet. The later 12 bolt covers are a little taller & the head gasket has a THINNER piece of cork attached to the gasket. This would mean the earlier style covers are shorter.

I remember this from doing my recent rebuild with 2.0 pistons using a 71 head, 75 block & an early style timing cover without the extra 2 bolt holes. I needed to add an extra piece of gasket to the front because the 2.0 head gasket is like the later 1.9 ones with the thinner piece attached. I also have here with me to check: Felpro 10 bolt & 12 bolt head gaskets, NOS Opel early & late head gaskets & aftermarket 2.0 head gaskets.

~ Tom C
Pgh PA
 

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Discussion Starter · #13 ·
The Saga Continues

Well, the SportWagon is here. John Warga and I spent the afternoon retrieving it from his house and towing it to mine. It looks a bit forlorn, tucked up alongside my Lexus IS300, sitting on the narrow strip of grass beside my driveway. But not as forlorn as Myrna did when she came to the realization that it had actually come to stay.

Nor as forlorn as I probably looked later in the afternoon, when John and I visited the machine shop that has the SportWagon's engine. The news? Well, I had already been told that the head was cracked completely through at one of the exhaust valve seats, but the machine shop has a '70 head that he will sell me for $75. Plus all the machining that needs to be done, including exhaust valve inserts, new cam bearings, & possibly new valves.

But he also had now measured the cylinders, and one is 8 thou out of round, and another has 10 thou taper. So that means I need four new pistons, at least 20 thou-over. So that will cost $350 US (about $475 CAD) for pistons, rings and pins. We discussed the possibility of using the substitute Chevy 265 pistons, but they weren't that much cheaper, and requires a major over-bore and the 2.0 head gasket. So a call to OGTS is in order, and an order for a set of whichever pistons Gil suggests will be placed. Probably a set of 30 thou-over flat-tops, unless he convinces me that the 2.0 pistons and head gasket is a better choice.

Finally (as if!), the cam that Harold Collins gracefully donated to the cause proved to be unserviceble. One of the lobes was already "flatted", so a new cam will also be coming.

Overall, a very discouraging afternoon. But, on John's sage advice, I think the GT engine, currently hanging from the rafters and the subject of a truly "economical rebuild" 15 years and zero miles ago, is about to become the new Ascona engine. If I am going to spend big bucks on an engine rebuild, it will be on a car that I actually will enjoy driving. Not that I won't enjoy driving the SportWagon (and apologies to Gene and the rest of the Ascona crowd), but the GT is really my first love. The SportWagon will have to make do with a low compression 1.9, at least until I stumble upon a surplus 2.8 V6 with a 5 speed. AFTER the GT is finished and well-driven.
 

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Keith, I think I would opt for a 3.4 vice a 2.8, same size block, but more power and the early, well actually up until the 3.1 and earlier engines had suspect crank bearing sizes. And with the SFI manifold, it's a lower engine overall than a carbed and coil/distributor ignition engine. JMYTCW.

Ron
 

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Maybe I missed it in this thread, but the simple question I need answered is can a 12 bolt head be used on a 10 bolt engine? Can you simply drill and tap the holes in the timing chain cover or would you just leave the extra holes empty?
 

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There's no material to drill and tap into on the early timing covers. Just leave the bolts out. But use the 10-bolt gasket.

Bob
 

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Discussion Starter · #19 ·
Sportwagon75 said:
Keith - Check out this guys Ebay store. He's got 15 pages of stuff that include lots of pistons, rings, bearings and miscellaneous stuff. Most of it cheap. Just a possibility. http://stores.ebay.com/Northern-Auto-Parts-Warehouse_W0QQsspagenameZl2QQtZkm
Eighteen pages tonight, 515 items. And not a single Opel CIH part among them.

But I think I have it beat. I am just waiting on a set of OP3 three-bearing cam bearings for the "triangle" marked head (bigger journal diameters in this head than the "asterick" head, and also bigger than the later four bearing cam journals. They are "in transit". I bought a set forged 0.040" over Flat-top pistons from RallyBob for the '75 engine, and just scored a set of NOS Hepolite .020" over flat tops with rings and pins on eBay for $160 for the '71 engine. The '75 is going back into the SportWagon, with a three bearing cam head, the stock EFI, and a stock cam. The '71 is going back into the GT, with the OGTS Combination cam, and a 38 DGAS. Valve train is staying stock for now, but that may change by the time they get installed.

What I HAVE learned (aside from the numbing cost of rebuilding TWO CIH engines at once!), is that the heads, blocks and chain cases are interchangeable between the years. The only real difference is the height of the timing chain case. Early models are shorter (below the block deck) , and need a cork front gasket on the head gasket, and the two extra bolts get deleted (even if a 12-bolt head is used; just apply some RTV around the bolt holes). Later models are flush with the block top, so need to be shaved the same amount if the block is decked, and the later (non-cork) head gasket is used. And they need the two front bolts ONLY if the 12 bolt head is fitted. Otherwise, use RTV to seal the holes, and only ten bolts.

HTH. I know it did for me
 
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